Ristocetin-induced platelet aggregation for monitoring of bleeding tendency in CLL treated with ibrutinib

Bleeding because of impaired platelet function is a major side effect of the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib. We quantitatively assessed ristocetin-induced platelet aggregation (RIPA) in 64 patients with chronic lymphocytic leukemia (CLL) under ibrutinib at 287 time points. Eighty-seven bleeding episodes in 39 patients were registered (85 Common Toxicity Criteria (CTC) grade 1 or 2, 2 CTC grade 3) during a median observation period of 10.9 months. At times of bleeding, RIPA values were significantly lower (14 vs 28 U; P<0.0001). RIPA was impaired in patients receiving concomitant antiplatelet therapy or anticoagulation (14 vs 25 U, P=0.005). A gradual decline of median RIPA values was observed with increasing bleeding severity. Importantly, no CTC grade 2 or 3 bleeding were observed with RIPA values of >36 U. Sequential monitoring indicated a decrease of RIPA values from a median of 17 to 9 U within 2 weeks after initiation of treatment as well as an increase above the critical threshold of 36 U within 7 days when ibrutinib was paused. Low RIPA values were similar during treatment with another BTK inhibitor, CC292. Quantitative assessment of platelet function is a practical tool to monitor bleeding tendency under BTK-inhibitor therapy.

Rituximab serum concentrations during immuno-chemotherapy of follicular lymphoma correlate with patient gender, bone marrow infiltration and clinical response

BACKGROUND

Treatment of follicular lymphoma with rituximab is currently recommended at a dose of 375 mg/m(2). We aimed to provide a rationale for optimal dosing and scheduling of this anti-CD20 antibody based on pharmacokinetics.

DESIGN AND METHODS

Clinical efficacy of immunochemotherapy with rituximab, fludarabine and mitoxantrone followed by 2-monthly rituximab maintenance was evaluated in 29 patients with previously untreated follicular lymphoma in a prospective phase II trial (AGMT-NHL9). Pharmacokinetic analysis was assessed in 17 patients.

RESULTS

Induction treatment resulted in high clinical response rates (complete remission 66%; ORR 100%). Significantly higher complete remission rates were observed in female patients (86 vs. 47%; Odds Ratio 6.8, 95% CI: 1.12; 41.82; P=0.05). Rituximab pharmacokinetic analysis showed a high variability ranging over almost 1 order of magnitude at maintenance cycle 1 (area under the curve 1,540-12,025 g/L*days). Median area under the curve was lower in men (81%) and in patients with initial bone marrow infiltration (76%). Higher rituximab serum concentrations before next therapy (C(trough)) were associated with female sex (P=0.04) as well as with absence of initial bone marrow infiltration (P=0.001). C(trough) correlated with remission quality (complete vs. partial remission; P=0.005) and progression-free survival (P=0.03). A decline in rituximab C(trough) below 25,000 ng/mL was observed 9.5 to 62 months before clinical relapse (P=0.008).

CONCLUSIONS

The results of this pilot trial suggest that more differentiated dosing schedules based on gender and bone marrow infiltration should be explored for rituximab therapy for lymphoma. This study was registered in ClinicalTrials.gov (Identifier: NCT01560117).

Prolonged progression-free survival in patients with chronic lymphocytic leukemia receiving granulocyte colony-stimulating factor during treatment with fludarabine, cyclophosphamide, and rituximab

The clinical benefit of the addition of granulocyte colony-stimulating factor (G-CSF) to standard immunochemotherapy of chronic lymphocytic leukemia (CLL) with fludarabine, cyclophosphamide, and rituximab (FCR) is still unclear. In this retrospective study we analyzed the outcome of 32 consecutive patients with CLL during treatment with FCR. Sixteen patients received G-CSF for treatment of CTC grade 3 or 4 neutropenia or febrile neutropenia at some point during therapy and 16 did not. Both groups were well balanced for clinical and biological risk factors. Overall response rates were not significantly different (94% vs. 75%; p=0.144). Interestingly, a significantly better progression-free survival (100% vs. 35.4% at 24 months; p<0.001) and even overall survival (100% vs. 77.8% at 24 months; p=0.022) was observed in patients receiving G-CSF. While the underlying cause remains to be elucidated, these data strongly suggest an association of the addition of G-CSF to FCR therapy with final patient outcome.

Compatibility of plastics with cytotoxic drug solutions-comparison of polyethylene with other container materials

In this study low density polyethylene (LDPE)-containers were compared to glass bottles and polyvinyl chloride (PVC) bags in view of adsorption effects with antineoplastic drugs. The infusion containers were supplemented with therapeutic doses of the nine common cytotoxic drugs carboplatin, carmustine, cytarabine, dacarbazine, fluorouracil, gemcitabine, melphalan, methotrexate and vinorelbine. 0.9% isotonic sodium chloride solution and 5% dextrose served as infusion solutions. The containers were stored at room temperature or at 4 degrees C, protected from light, for periods of up to 168 h. Turbidity, change of colour and visible crystallization were not observed. Samples were collected at different time intervals and drug contents were determined with high-performance liquid chromatography (HPLC). Preparations of carmustine showed no adsorption phenomena when stored in LDPE or in glass at 4 degrees C. At room temperature in LDPE, a slight decrease in concentration due to adsorption was monitored. However the drug loss in PVC bags was greater. Dacarbazine and melphalan showed decreases in concentration, which were independent on the type of container material. The remaining analyzed agents showed no drug loss at all. In conclusion, investigated drugs were stable in all three container types, with the best stability in glass bottles, followed by LDPE and PVC.